Question about 1999 Ford Explorer

1 Answer

When I run car MD or another code reader I get lean fule readings

Have changed the fuel filter and tested the MAF SENSOR (MASS AIR FLOW). Engine light still comes on, what else should I check before pulling fuel injectors and cleaning them (note reader says only bank 2)? Would the IAT (intake air temp) also cause the reading? Would you recommend any thing else to check?

Posted by on

1 Answer

The only way to clean fuel injectors- is to remove them &
you mail them away, to a place to be tested & ultrasonically
cleaned,no other way ,so forget that

You come here for suggestions--but provide no codes

The codes & proper manuals & charts to follow--will walk you
thru the diagnostic process

You did not provide a motor, or what the issues are, or the codes,
or any details on testing ,how it was done & the results.

Bank 2-- is the left side of your motor & the MAF is common to
both sides,(need your thinking cap on here)

At least you so far, haven't thrown parts at it, as most people do
That is a good start

Posted on Dec 09, 2012

  • 6 more comments 
  • lillieIII Dec 10, 2012

    So sorry ,the code is PO174 bank 2 4.0 l SOHC V6

  • Anonymous Dec 10, 2012

    PO 174 System too lean (bank 2) You can google any obd2 codes Most likely a failed upstream sensor .You won't have the ability to test as I would so I suggest you replace both sides if you have dual exhaust when you reach 100,000 miles or as you have a possible failed sensor

  • Anonymous Dec 10, 2012

    Nornally I don't suggest replacing any parts as a vacuum leak could be any issue or other problem but it is just on one side of the motor I you have the ability to road test with a pro type scan tool you could look at fuel trim & other data & get to the conclusion faster

  • lillieIII Dec 10, 2012

    tHANK YOU MUCH, AFTER READING FUTHER i DID REMEMBER THE maf SENSOR HAD DIRT ON ONE OF THE THIN WIRES, AS iT ISM NOW SNOWWING i WILL CLEAN THIS IN THE MORNING AND THANKS YOUR ADVICE HAS BEEN EXTREMELY HELPFUL

  • Anonymous Dec 10, 2012

    Keep in mind that the MAF is common to BOTH banks You still have a possible bas oxygen sensors they slow down at 100,000 or fail They control injector pulse width by switching voltage they output to pcm

  • lillieIII Dec 10, 2012

    Peter, I will let you know of the results, thanks again and have a great holiday.

  • lillieIII Dec 16, 2012

    Peter i ended up being the O2sensor thank you for the help

  • Anonymous Dec 16, 2012

    Welcome

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Posted on Jan 02, 2017

warlock61
  • 659 Answers

SOURCE: check engine light

this is very common on these. the upper intake seals leak and should be replaced. It is not a noticable vacuum leak and is usually worse when the engine is cold. It is not a very difficult job to do

Posted on Mar 01, 2009

Molson02536
  • 3854 Answers

SOURCE: check engine light

It might but what exactly are the codes. Before you change the Mass air flow sensor, try cleaning it first with a can of mass flow cleaner.
If your running a oil K&N filter, there could be some oil residue on the sensor. Start with that and change the filter or clean it if it's a K&N.
The O2 sensor's could be bad also, you really need the code's to be sure what sensor is giving you the faulty signal.
Good luck and hope this helps.

Posted on May 05, 2009

autodr
  • 260 Answers

SOURCE: Cleaning the Mass Air Flow Sensor

i will try to help. 171/174 indicates lean condition in engine. the mass air flow sensor is located in the rubber tube going to throttlebody. you can try to clean it. using mild carb cleaner safe for sensors, remove sensor from tube. spray clean the tiny wires located in the cylinder. do not touch them, they are very delicate. these engines are also notorious for leaking intake gaskets and faulty pcv valves. these will all set these 2 codes. feel free with anymore questions.

Posted on Nov 15, 2008

pippall
  • 1486 Answers

SOURCE: ford 4.6 code po174 bank 2 too lean

O2 sensor faulty.

Posted on Jul 18, 2009

fingaz22
  • 1068 Answers

SOURCE: TOO LEAN CODES

yes very very common code for these motors i get them all the time. now the first thing i do is listen to the pcv valve for noise if it is rattling this is the problem and is the most common of all. another thing is the intakes leak from cracks in them but the only way to find it is with a smoke machine. now the one other thing i have seen before is debre like a leaf in the mass air flow sensor but you have replaced it so most likely no that.

do your self a favor and change the pcv valve it only cost under 5 dollars. if this is not it you will need to find the leak in and around the intake or a vacuum hose.

because you have two lean banks this mean if it is a leak then it has to be in common with both banks and that is the vacuum line system intake etc...

let mew know if you have any more question. good luck man

Posted on Oct 21, 2009

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3 Answers

2003 Nissan Altima 2.5L Service Engine Soon Light is on, Auto Zone says codes are for MAF and O2 Sensors. Car hard to start after driving a while but when starts appears to run smooth. Auto Zone thi


ok lets start with the codes they say your getting. P??? which 1's and how many. there are few o2 sensors, are they next to the Exhaust next to the converter? MASS AIR FLOW -MAF use this, for now i am guessing, until i see the correct codes your are getting. this could be the 1 you may have below, please read it........
  • P0103
    Mass Air Flow Sensor Circuit High Input
  • Possible causes
  • Faulty mass air flow sensor
    - Intake air leaks
    - Dirty mass air flow sensor
    - Dirty mass air filter
    - Mass air flow sensor harness is open or shorted
    - Mass air flow sensor circuit poor electrical connection
  • Before replacing the mass air flow sensor, try replacing the air filter and cleaning the air flow sensor with low compress air or mass air flow sensor cleaner. Reset code and drive vehicle. If the code comes back, it may be necessary to replaced the mass air flow sensor.
  • possible symptoms Engine Light ON (or Service Engine Soon Warning Light)
    - Engine stall
    - Engine running rough
    - Excessive fuel consumption
    - Excessive smoke
  • the code is generated when An excessively high voltage from the sensor is sent to Engine Control Module (ECM).
2003 NISSAN Altima Sedan OBDII Codes List

Oct 22, 2014 | 2003 Nissan Altima

1 Answer

2000 nissan sentra 2.0 error codes p0101& p0102


P0102 - Mass Air Flow Sensor Circuit Malfunction

The mass air flownissan-maxima-maf-sensor.jpg or MAF sensor is placed in the intake air duct between the air filter and the engine intake manifold. The MAF sensor measures the amount of intake air flow. The MAF sensor converts the air flow measurement into a voltage or frequency signal, with the voltage or frequency changing proportionally to the amount of air flow. The air flow sensor signal is monitored by the engine computer (ECM). The engine computer (ECM) uses the mass air flow signal to know the engine load and to calculate the proper amount of fuel injected. If the signal from the mass air flow sensor is out of expected range, the ECM detects a fault and sets the code P0100. For example, the mass air flow sensor signal could be higher than expected when the engine is not running or lower than expected with the engine running. A car with the code P0100 may have some driveability issues, such as stalling, lack of power, surging, hesitation, etc. In some cars, the code P0100 can cause the fail-safe mode where the engine speed would be limited to 2,500 - 3,000 rpm.
If there are other trouble codes present, they might need to be looked at first. Checking the freeze frame may help, as it may contain some important information. The freeze frame is a snapshot of the engine parameters at the moment when the fault was detected. The freeze-frame may show whether the vehicle was running or stopped, whether the air-fuel ratio was lean or rich, was the engine was cold or warmed up at the time of the malfunction. Read more about the freeze frame.


Read more about mass air flow sensor.

What could cause the code P0100:
- faulty or contaminated mass air flow sensor
- open or short in the mass air flow sensor electrical circuit
- open or short in the sensor power or ground circuit

- other electrical problem with the MAF sensor wiring, (corroded wires, bent terminals, bad ground connection, burned fuse, etc.
- vacuum leaks
- restricted air flow at or before the air filter
- wrong air flow sensor installed
- problem with ECM





P0102 - Mass Air Flow Sensor Circuit Low

The mass air flow or MAF sensor measures the amount of air entering the engine. The engine computer (ECM) uses the mass air flow signal to calculate the amount of fuel injected (read more how the MAF sensor works below). The code P0102 is set when the signal from the mass air flow sensor is lower than expected. Often a car may exhibit some driveability symptoms, such as lack of power, surging, hesitation on acceleration, hard starting, pinging (detonation), or rough idle when started cold. Often the codes P0171 or P0174 could also be stored along with the code P0102, as the incorrect air flow signal can cause the engine to run lean. The codes P0171 and P0174 indicate a lean condition. Checking the freeze frame might help in the diagnostic process. The freeze frame is stored in the ECM along with the trouble code. The freeze frame contains some recorded parameters (e.g. vehicle speed, engine temperature, fuel trim) at the moment when the fault was detected. The freeze frame can also be accessed with a scan tool.



What could cause the code P0102
- faulty or contaminated mass airflow sensor
- debris blocking the air flow at the mass air flow sensor
- unmetered air leaking past the MAF sensor (vacuum leaks)
- PCV system vacuum leaks
- restricted or collapsed intake air duct
- dirty or restricted air filter
- restricted air screen before the air filter
- improper application of aftermarket components (e.g. cold intake, modified air filter, etc.)
- wrong air flow sensor installed
- electrical problem with the MAF sensor wiring, connector, power supply or ground.
- problem with ECM
- in some cases other issues with the fuel injection system like a clogged catalytic converter or a faulty manifold absolute pressure sensor (MAP) can also cause the code P0102.




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Check engine light is on, tested with OBD reader and got P0171 system too lean bank 1 result.


There could be a vacuum leak downstream of the Mass Air Flow sensor or the Mass Air Flow Sensor is dirty or faulty. Try cleaning the MAF sensor wire elements and clear the engine computer code. After removing the MAF sensor, spray the honeycomb inside the sensor, or the air meter with electronics cleaner or brake cleaner. Make sure you are careful not to damage the MAF sensor, and make sure it's dry before reinstalling. Inspect all vacuum and PCV hoses, and replace any vacuum hoses that have cracks, cuts, etc. If it has been a long time since you changed your Fuel filter, it may be a good time to do this as well. This could also be due to a faulty O2 Sensor.

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  • P0171 - Fuel Trim System Lean Bank 1
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  • Would start with the mass air flow sensor the other two codes may have been triggered by the performance of the MAF sensor. Is the vehicle running poorly or have high or low idle?

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    2004 denali check engine light stays on


    There is no p01001, it's either p0100, or p0101.
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    The mass air flow sensor can cause the 02 sensors to read lean.
    The u1301, is a class 2 circuit short to battery. That, you have to test wires to find with a voltmeter/continuity tester.
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    A lean code can be caused by several different things. The most common, if you are getting a lean code on BOTH banks, is a dirty Mass Airflow Sensor (MAF) Cleaning the MAF usually fixes it.

    If not, it could be caused by anything from a crack in a vacuum line to a bad fuel pump. (Anything that could make the engine run lean.)

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    The lean running codes are related to the p-1000 code...

    Running lean on bank 1 and bank 2 means your oxygen sensors sense too much oxygen in your exhaust flow. This means either your engine is getting unmetered air (air that the engine does not know is coming in, therefore does not send fuel to compensate for...) (air that your mass air flow sensor does not see). You could have either a bad mass air flow (MAF) sensor (in the intake piping after the filter; this sensor tells your engine how much air it's taking in, so it can send the right amount of fuel through the injectors to properly burn with the air available with as little emissions as possible), or you could also have a cracked/broken intake piping after this sensor which lets air in the intake that the sensor does not measure... A large vacuum leak could also let unmetered air in the engine.

    Or... Another possibility here would be low fuel pressure (bad fuel pump, bad fuel pressure regulator, fuel leak), as not enough fuel for the air would also cause the same lean condition.

    It could be that some oxygen sensors are bad...

    These conditions are hard to pinpoint exactly unless you have a scanner that can read sensor data (MAF Flow, fuel pressure, oxygen sensor values)...

    The first thing I'd do would be to check for cracks or damage in the intake piping... If there is none, then it might be a low fuel pressure issue, or sensor problems...

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